GSMaintenance: Put your site in "Maintenance mode"

[Tyblitz]

it would be (as maf already said) a great feature when the admin could still see the website (perhaps trough adding their IP ? )

This is pretty simple to achieve in the GS3.1+ versions. GS sets a cookie to tell it whether the admin is logged in. Hide the webpage when the cookie is not present:

PHP Code:

global $USR;
if (isset($USR) && $USR == get_cookie('GS_ADMIN_USERNAME')) {
  // do nothing
} else {
  // hide website
} 


As for the Dutch translation, "Schakel Onderhoudsmodus in/uit" would be even more correct (although it doesn't matter that much).